Fiber-optic communication involves transmitting information between devices by sending light waves through an optical fiber. Fiber-optic communication systems have revolutionized the telecommunications industry and have played a major role in the evolution of the Internet and the sharing and transmitting of data in general. With numerous advantages over electrical transmission, optical fiber-based communications are replacing copper wire based communications in networks throughout the world.
Wavelength-division multiplexing (WDM) is a technology that combines, or multiplexes, optical carrier signals on a single optical fiber using different wavelengths (colors) of light. Stated differently, data is not only encoded into a wave of light but also into discrete wavelengths. With WDM, the capacity of an optical network can be dramatically increased as each fiber can carry many different wavelengths of light.
Many optical networks, particularly long-haul (i.e., those networks covering vast distances) and metro networks, include a device or service typically referred to as a ROADM (reconfigurable optical add-drop multiplexer). Generally speaking, a ROADM allows traffic in an optical system to be switched, based on the wavelength of an optical signal. So, without converting the optical signal to an electrical one, a particular wavelength of light can be identified and switched between fibers, or otherwise added or removed from a multiplexed wave bundle. Additionally, a ROADM may be used in conjunction with a regeneration device to regenerate various wavelengths as those wavelengths diminish over various distances. At some point the wavelength diminishes to a level that can no longer be used unless it is regenerated.
The capital costs for regeneration are significant since a regeneration card is needed for each individual wavelength (potentially in the hundreds) traveling over a fiber. Additionally, regeneration may be a significant portion of the overall cost of a network. Moreover, power costs, facility costs, maintenance and other costs for high speed regeneration equipment can be substantial.
Placement of ROADMs and regenerators in an optical network has often been ad-hoc and/or overly dependent on geographical locations of metropolitan areas. Hence, for example, when metropolitan areas are relatively close (e.g., less than 800 miles), then redundant and unnecessary ROADMs and/or regenerators may be placed inefficiently too close to each other. Similarly, when ROADMs are placed in the network, they may add noise to the fiber, requiring more frequent regenerations. For example, ROADMs placed in a network to service a particular customer circuit or circuits, such as in various metropolitan areas, may degrade the other signals that must pass through the ROADM but may not require regeneration. Thus, inefficiently placed ROADM and regeneration devices may have substantial impacts on a fiber network.
It is with these problems and issues in mind, amongst others, that various aspects of the present disclosure were developed.